The general rule is that all questions on beta software and services are off-topic, out of scope, and should be closed on Ask Different according to our FAQ. However, we now have two shipping products that are highly friendly and desirable to end users yet still in beta:
Would sticking to our FAQ and closing all questions on these two products be more ridiculous than editing their tag wikis to indicate that we are consciously waiving the Beta prohibition on these due to the wide dissemination, huge audience, and/or utility to our users to have a forum on these "indeterminate" beta products from Apple?
There are no signs Siri will be out of beta despite selling millions of iPhone 4S weekly since October 4, 2010. All signs point to Messages being generally and widely available for 6 or more months until OS X Mountain Lion ships.